How to Keep Your SCOBY Healthy and Mold-Free

Homebrewers are often worried about their kombucha SCOBY care. SCOBYs are generally pretty tough. A healthy SCOBY can come in all shapes, sizes, and colors. And you can make delicious tasting kombucha even if your SCOBY does not look like a light-colored flat pancake. Here are some tips and tricks to help maintain a healthy kombucha SCOBY.

SCOBY Maintenance

Although SCOBYs are pretty hearty, a little love and affection will go a long way. A mother SCOBY will naturally produce a baby SCOBY during each fermentation. This continuous cycle allows us endless kombucha if maintained correctly.

Follow the below steps to help your SCOBY family grow and to keep the kombucha flowing:

• Store in clean glass jars to help keep them safe.
• Never refrigerate SCOBY. Always keep at room temperature.
• If SCOBY gets too big, cut into smaller pieces to use separately.
• Don’t remove the stringy yeast unless there is excess build up. This helps develop carbonation and keep pH balanced.
• Peel off top layers (and dispose the oldest) for best SCOBY health.
• If continuous brewing, keep an appropriate amount of starter liquid for SCOBY size.
• Too little and it will be flat
• Too much and it will be acidic

How to prevent mold on SCOBY:

Mold is definitely a buzzkill. Mold on kombucha is actually rare and can be handled easily so no need to panic. But it can disrupt the flow for home brewers so always best to take preventative measures. To keep the good times rolling, follow some easy steps below.

• Always ensure plenty of airflow for the SCOBY to breathe. Do NOT keep your fermenting jar in any enclosed spaces.
• Do NOT expose the brew to cigarette smoke or other contaminants.
• Always use filtered or purified water to prevent contamination.
• Ensure starter liquid is not flavored with fruits or juices during first fermentation.
• Keep your brew around room temperature (68 to 77°F) or slightly warmer. If too cold, the fermentation process will slow down giving more opportunities for mold to form.

NOTE: You can wrap the jar with a heat blanket or place near the side of a refrigerator to warm up. But remember, SCOBYs don’t like it too hot, either. (Think of it as Goldilocks’ baby bear needing everything just right).

How do you know if your culture has mold?

Mold on a SCOBY looks exactly like the mold you would find on old bread. It may appear as white, blue, green or black fuzzy patches. It will grow on top of the SCOBY culture where it is most exposed to airborne bacteria. Mold most likely occurs due to the following reasons:

• Storing your SCOBY in cold temperatures
• Using weak or too little starter liquid
• An imbalanced pH (best range is between 2 and 4)
• Using impure ingredients to make your sweetened tea
• Fruit flies or other contaminants inside the brew

What to do if you find mold on your SCOBY?

Toss the moldy SCOBY and the remaining contents in the jar ASAP! Do NOT try to salvage the remaining liquid/SCOBY as it is a major risk to your health.

Sterilize your container before trying another brew with new starter liquid and SCOBY.

What to do if you have a thin SCOBY?

Although SCOBYs come in many shapes and sizes, a healthy baseline is reaching about a quarter-inch thickness by day 10-14. First-time SCOBYs can take longer to ferment. Your best bet is to keep the little guy warm and let the process do its work. 

How do you know if your SCOBY is dead?

Although tannins in tea can darken the color of the culture (totally normal), a dead SCOBY will most likely appear black.

A dehydrated kombucha SCOBY will be dry and leathery. Both types are goners and need to be thrown away.

Sometimes after a SCOBY has been used for multiple batches, the culture will weaken and disintegrate. This usually means the SCOBY lifespan has run its course and it's time for a replacement.

What to do if you have a sinking SCOBY?

A SCOBY may move around during the first week or two of brewing. Factors like temperature changes and co2 distribution in the brew can affect the SCOBY sinking or floating to the top. Never fear! As long as your starter tea is good, the fermentation process will still be going strong.

Do your best to regulate the temperature to keep your brew warm and cozy. Try using a heat wrap if necessary during winter months and you will be seeing growth in no time.

How many times can you use the same culture to brew kombucha?

We recommend using a healthy SCOBY up to 5 or 6 times. If you notice your culture start to disintegrate or turn dark brown, it is a sign of a bad kombucha SCOBY. It is time to brew with a newer culture.

Sometimes the new culture will combine with the original SCOBY. This is completely fine. However, if a thick SCOBY covers the entire surface of the jar it may inhibit proper ventilation. In this case, either peel off the old layer or cut in smaller pieces to use separately.

Scoby storage

Will you be taking a break from brewing or going on vacation? Learn how to run a scoby hotel for longer-term storage.

Happy brewing! 🙂